The order Dermoptera contains only two species of flying lemurs, also known as colugos. These arboreal, nocturnal mammals are native to southeast Asia. Flying lemurs, as their name suggests, possess well developed gliding membranes; however, they cannot achieve true flight. Flying lemurs are not true lemurs, but were once lumped into the order Insectivora. Flying lemurs in reality are strict herbivores. Colugos have highly distinctive incisor teeth; they are comb-like in shape, with up to twenty tines on each tooth. The second upper incisors have two roots, another unique feature among mammals.